Cast or wrought steel components for use in railway stock, mining tools and equipment and industrial machinery are often subject to excessive and premature wear. The steel from which these components are manufactured is usually chosen for its ready availability and cost effectiveness, and not necessarily for optimum strength, hardness and resistance against wear or abrasion. Some steel alloys have a mixed microstructure which is not conducive to use in applications where high strength, high impact resistance, and reduced wear are required.
It is known to ‘hard face’ standard grade steel cast or wrought components by welding a matrix of material which includes hard particles, such as tungsten carbide particles, onto a surface of the component to provide a hard outer layer of material. Typically the carbide used is a low cost material sourced from pre-ground tool bits and tips, and is of random particle size and shape. After welding in conventional hard-facing processes, the region of the steel component closest to the welded layer is often heat affected, and may have a different metal microstructure as a result of the heat applied during the welding. The surface of the component can thus become brittle and thus lack toughness and impact resistance. Cracks between the steel component and the exterior hard-facing can propagate under load.